The present invention relates to a steel laminate gasket with a seal protecting member near the outer periphery of the gasket.
A gasket is installed between two engine parts to seal therebetween. In order to securely seal around a hole of the engine parts, the gasket is provided with sealing means around the hole, which provides high surface pressure when the gasket is tightened.
When an engine is operated, the engine together with the gasket vibrates, wherein the vibration is especially severe at a periphery of the gasket. Especially, a cylinder head gasket receives a severe vibration at the periphery thereof.
When the gasket vibrates, sealing pressure applied against the sealing means around the hole changes repeatedly. As a result, when the gasket is used for a long period of time, creep relaxation occurs at the sealing means. Also, when coatings are formed on the plates, the coatings may break or gradually flow outwardly by the vibration of the gasket.
In Japanese Utility Model Applications No. 63-12261, No. 63-20827 and No. 63-53125, it was proposed that at least one protecting plate is formed at an edge portion of a gasket near a hole to be sealed, so that vibration of the gasket is reduced. In these inventions, vibration of the gasket is properly reduced, but it requires additional plates.
Accordingly, one object of the present invention is to provide a steel laminate gasket, in which sealing means around a hole is protected from vibration of the gasket.
Another object of the invention is to provide a steel laminate gasket as stated above, wherein creep relaxation of the sealing means is substantially prevented.
A further object of the invention is to provide a steel laminate gasket as stated above, wherein the flow of the seal coating formed on a gasket is substantially prevented.
A still further object of the invention is to provide a steel laminate gasket as stated above, which can be easily and economically manufactured.
Further objects and advantages of the invention will be apparent from the following description of the invention.